1. Field of the Invention
The present invention relates to an apparatus and method of use for measuring the geometry of a foot in the position the foot will be in when inside of a shoe. More particularly, the present invention relates to an apparatus having a foam impression block specially formed into the shape the target foot wear will have. Moreover, the present invention relates to methods of using such an apparatus for measuring the plantar contour and instep of a foot in the position the foot will be in when inside of a shoe.
2. Description of the Related Art
A number of methods currently exist to measure the geometry of the plantar contour of a foot. The accurate measurement of the plantar contour is used in the manufacture of custom insoles. The prior art methods include plaster casting, optical scanning, contact sensor measurement, as well as foam impression measurement. These methods require the foot to be in a planar position. However, some shoes, such as high heels or other shoes with a slope, distort the plantar contour and instep due to the shifting of the user""s body weight. Accordingly, the insoles made using these prior art methods do not account for such distortions. Moreover, these prior art methods are not well suited for home use.
The optical scanning methods and contact sensor measurement methods utilize expensive equipment. These methods provide an accurate and complete measurement of the foot. But, the size, expense and complexity of the equipment necessary for these methods makes them not suitable for use in all locations. Moreover, these methods do not permit accurate measurement of the geometry of the foot in the position it will be in when inside of a shoe.
Plaster casting methods require the measurement to be performed by a person other then the one being measured. This method provides an accurate and complete measurement of the foot but can be very messy and time consuming. Thus, plaster casting methods are not suitable for use in a person""s home or by one""s self. Moreover, these methods do not permit accurate measurement of the geometry of the foot in the position it will be in when inside of a shoe.
Foam impression measurement methods and apparatus utilize an easily deformable foam block. A person steps onto the block, thus crushing the foam in the locations of higher pressure. In this manner, the foam block deforms in the approximate shape of the persons"" plantar contour. While this prior art method may be suitable for home use, it produces a sub-optimal characterization of the foot for a number of reasons. First, the foam block is uniform in thickness from heel to toe. This causes the toes to be forced upward as the foot is pressed into the foam because the toes of the foot have substantially less pressure on them than the region of the foot from the heel to the metatarsal heads. Forcing the toes upward can cause a number of problems including, hyper-extension of the plantar fascia, lowering of the correct arch height, and improper measurement of the forefoot and heel. Second, under full body weight, the foot expands allowing for a larger than normal foot impression. Additionally, the prior art does not provide for measurement of the instep. Moreover, the current foam materials and methods do not permit accurate measurement of the geometry of the foot in the position it will be in when inside of a shoe.
In the manufacture of custom insoles, the use of the plaster casting and foam impression methods also require the use of a scanning system. The scanning system may act directly on the negative impression within the foam or plaster. Scanning systems that act directly on negative impressions are known in the art. These laser scanning systems consist of a laser with a line generating optic. The laser projects a line at a know incident angle onto the negative impression. A camera is used to read the position of the laser line on the negative impression. Alternatively, the scanning system may act on a positive plaster model made from the negative impression within the plaster or foam. Scanning systems that act directly on the positive impressions are also known in the art. One such scanning system, provided by U.S. Pat. No. 4,876,758, specially constructed array of pin-like sensors. In either circumstance, the scanning system is used to digitize the measured contour. The digitized contour is provided to a computer controlled milling machine. The milling machine uses the digitized information to manufacturing a custom insole matching the digitized contour. Accordingly, the apparatus and methods of the present invention provide for cheaper and easier means to provide custom manufactured insoles to a customer.
Accordingly, it is an object of the present invention to provide foot measurement apparatus and methods, which overcome the limitations set forth above.
It is an object of the present invention to provide an apparatus for measuring a plantar contour. The apparatus has a foam impression block, and a carrier having a heel. The block has a toe thickness, a length and a heel thickness. The toe thickness is less than the heel thickness. The block is disposed upon the carrier such that the heel thickness and the heel are adjacent one another.
It is a further object of the present invention to provide an apparatus for measuring a plantar contour and an instep. The apparatus has a foam impression block and a carrier. The carrier has a heel and a plurality of straps. The block has a toe thickness, a length and a heel thickness wherein the toe thickness is less than the heel thickness. The block is disposed upon the carrier such that the heel thickness and the heel are adjacent one another. The plurality of straps are disposed upon the carrier and are adapted to wrap around the instep such that a plurality of sizing graduations disposed upon each of the straps are readable.
It is also an object of the present invention to provide a method for measuring the plantar contour of a foot. The method having the steps of: (1) placing the plantar contour over a foam impression block disposed upon a carrier having a heel wherein the block has a toe thickness, a length and a heel thickness, the toe thickness is less than the heel thickness, and the block is disposed upon the carrier such that the heel thickness and heel are adjacent one another; (2) aligning the toes with the toe thickness; and (3) urging the plantar contour into the block to deform the block.
It is a further object of the present invention to provide a method for measuring the plantar contour and instep of a foot. The method having the steps of: (1) placing the plantar contour over a foam impression block disposed upon a carrier having a heel and a plurality of straps, wherein the block has a toe thickness, a length and a heel thickness, the toe thickness is less than the heel thickness, the block is disposed upon the carrier such that the heel thickness and the heel are adjacent one another, and the plurality of straps are disposed upon the carrier are adapted to wrap around the foot; (2) aligning the toes of the foot with the toe thickness; (3) urging the plantar contour into the block to deform the block; (4) wrapping the straps around the instep such that a plurality of sizing graduations disposed upon each of the straps are readable; and (5) noting the sizing graduation indicated by each of the straps.